It is known that, during generation of laser pulses, a modification of a laser medium occurs, and this has for example an effect on the power of the laser pulses generated. That is to say, the same excitation pulses do not always lead to the same output laser pulses in the same laser beam generator.
One known measure of increasing the influence of a laser medium being modified on the reproducibility of an output laser pulse generated by a radiofrequency excitation pulse is so-called “simmering”. In simmering, the laser medium is additionally excited by short simmer pulses between the excitation pulses that are used for generating a laser output pulse, where the excitation by the simmer pulses remains below the threshold of laser emission. The laser medium is thereby kept in a maximally constant state (close to the excitation threshold). For example, simmering is described in US 2012/189031 A1.
In DE 11 2013 002 021 T5, for a diffusion-cooled CO2 gas discharge laser, it is explained that, in the case of two successive identical radiofrequency excitation pulse sequences, the second output laser pulse has a lower laser power than the first output laser pulse. The reason for this difference is, according to DE 11 2013 002 021 T5, the introduction of heat into the laser medium by the first excitation pulse sequence, as a result of which the efficiency of the second excitation pulse sequence is reduced. In order to compensate for this, empirical enhancement factors for the second RF excitation pulse sequence are stored. The enhancement factors vary as a function of the time which elapses between the end of the first excitation pulse sequence and the start of the second excitation pulse sequence. The enhancement factors always cause an increase in the power of the second excitation pulse sequence, this being brought about in various ways. For instance, the pulses of the second excitation pulse sequence may all be lengthened in time, or additional pulses may be added in comparison with the first excitation pulse sequence.